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How Much Boost Will The Stock Boost Controllerhold


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You would be spiking to 20ish if your w/g wasn't working. I've run with it's actuator hose disconnected purposely before :)

Sounds like there might be a vacuum leak that doesn't always leak... Have you checked all the rubber elbows in your intake system?

If you think it's your BCS (I've gotten bad ones new from Volvo before), then bypass it and use a manual boost controller sole-ly to control the boost level. It sounds to me like a vacuum leak, but it's hard to say....

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Rubber lines just can't last forever. When they're 8-10 years old and have a bunch of heat cycles on them, they just die. If you're worried about vaccum leaks, just replace all your lines with new ones, silicon if you don't want to do it again for a while. ;) It will not cost much, and is a relatively short proceedure minus a couple of hard to reach connections.

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New info:

My piping and intercooler are new, no change before them and after.

Pluging in the cable didn't work this time. Disconnected the stock bcs and put a bleed in the line from the turbo presure source to the WG. Boost rose only 2 pounds and this is a large bleed, like 50%.

Could my Bov be leeking? Or could the WG be stuck partly open? I adusted it a million times, could I have jacked it up?

Update: Unpluged the WG line boost went up to 15psi and I let off.

Also my TPS is reading only 87.5% even though I am flooring the car. Haven't taken a reading when the car is running right.

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Guest Guest_volflo

hey pete.

since my car is back on the road for one week now, i have tested my times (80-180, 100-200, 60-100, 80-180 only forth) like last year.

along with the UR puley i also removed whole ac System (incl ac cooler so intercooler is in front now free breathing) , belt is now ~20 inch shorter than before)

car runs like hell now: from 100k to 200k i gained an unbelievable 2.5 secs. now my car jumps from 100 to 200k using 3 and 4th gear in.....

10,7 SECS :D

two people in the car. (three times under 11 secs)

80-180 in only 4th 10.8 secs.

60-100 2.8, 2.9

80-180 3rd 4 th gear 9.7 secs

im quite satisfied. GREAT JOB PETE.

but i think i have to adjust my wastegat now. How come that the pressure seems to have increased slightly? Anyone know?

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87.5% is the widest I have ever seen my TB open as well. I suspect that is the most the 850 TB will open, or that the comptuer just dosn't bother to register and value over this. It could be a power retardation feature, or a "saftey" feature (although I don't know why), but I can imagine it.

Maybe your wastegate is too weak, but I saw no difference in bleed on a 15g between the stock 185/65 wastegate and a 300/70 wastegate. Both bled off pretty evenly.

There was at one point a lot of dicussion about this, a lot of people had their Volvo with a chip/exhaust or just chip who would boost to 15psi, but bleed off to 10-12 psi. I honestly just think it's the Volvo and the turbo's flow rate.

Sure it works without your wastegate, but that eliminates the comptuer control over boost bypass and then wastegate itself, either of which could be the culprit. Could have some other effects I am forgetting to mention at the moment.

Edit: It may be a stupid question, but how is your compression?

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